"Brown's Political History of Oregon: Provisional Government: Treaties, Conventions, and Diplomatic Correspondence on the Boundary Question; Historical Introduction of the Explorations on the Pacific Coast; History of the Provisional Government from Year to Year, with Election Returns and Official Reports; History of the Cayuse War, with Original Documents."
by J. Henry Brown
Portland, OR: Wiley B. Allen, 1892.
Called "Volume I" but this is the only volume published. Most physical copies of the first edition seem to have been destroyed in an accident.
This edition scanned by the Google Books project has extraneous pages pared away and includes "Bookmarks" in the pdf denoting chapters.